Abstract
In order to study in detail effects unique to two-phase flow in helically coiled pipes a mechanistic two-phase flow model has been developed which is based on the RELAP5/MOD3 two-fluid mode, however with new and improved correlations for flow regime mapping, stratification and wall shear and heat transfer. The point of transition to stratified flow has been modified based on the Kelvin-Helmholtz stability criterion to better represent stratification onset in coiled pipes. Centrifugal forces acting on the flow has been accounted for by a modified body force with a subsequent nearly-implicit coupling in the momentum equations and a set of correlations representing the phasic wall friction factors and two-phase multipliers have been included in the code though in a modified form. This presentation summarizes the new correlations and the overall influence of the curvature of the flow path on the two-phase flow is estimated using a sample benchmark.
